Protective device



Sept. 23 1924-.

1,509,494 J. SLEPIAN PROTECTIVE DEVICE Filed Feb. 16, 1922 WITNESSES:

INVENTOR v L/b h 8/? m ATTORNEY vices,

Patented Sept. 23, 1924. l

Application filed February 16, 1922. Serial No. 586,910.

scribed a new type of lightning arrester comprising, primaril a series of plane plates or disks stacked in contact with each other, the said disks being composed of a material having a high specific resistance. In operation, the pile of disks is connected between a circuit to be protected and the ground so that, upon the circuit being subjected to abnormal voltage, sparking occurs between thelates causing a glow discharge to be established therebetween and allows the excess energy to flow to ground. Upon the return he circuit voltage to a value but slightly below the breakdown voltage, the glow dis charge ceams and substantially-no current passes to the ground.

After a discharge, it has been found that in man cases an appreciable power current flows or a considerable length of time. This is due to several causes, chief among which are the large area of contact between the disks, and the loose particles of material that are formed upon frequent discharge through the arrester.

v In view of this, one of the objects of the resent invention is to provide a plate or disk structure for my new lightning arrester which shall be eflective to reduce the power 1085 after discharge to a minimum.

It is a further object of this invention to rovide a simple disk structure which may he manufactured at a low cost and which shall be adapted to q uantity production.

11 practising my invention, I provide a disk structure embodyin a narrow, elevated portion or rib therein. referably, the rib is of material having a hi h specific resistance, nerally considerab y higher than that of the? disk itself. I stack a series of and]: disks so that h rib on ne face of one disk contacts with the smooth or plane face of the next adjacent di his provides a simple structure which hasa very hi h resistance to power current at a voltage low the discharge voltage of the arrester and still allows a ready path for a considerable volume of current above the discharge potential.

In the accompanying drawings, forming a part hereof, and in which like reference characters designate like parts;

Fig. l is a plan view of a disk made in accordance with this invention;

Fig. 2 is a side view of a pile of disks, an

Fig. 3 is' a cross sectional view on an enlarged scale of one of my disks.

e disks 1 are formed of any suitable resistance material, preferably, but not necessarily, of material having a high specific resistance. consisting of kaolin, carborundum and graphite, which are mixed in a slightly plas- I generally utilize a material tic state, molded in suitable molds to the form shown and then baked to dry the material and form the same into a solid, coherent, wear-resisting body. One surface of each plate is provided with a rib or ribs 2, preferably formed integrally with the plate either in the molding process or by sandblgsting the depressed portions between the n s I then provide a heated plate which is generally in annular form or sometimes of ri g form with The plate or 1 is placed so that the rib 2 is in contact with the heated ring. The time of contact is deter mined so that the heating burns or oxidizes the carbon in the rib 2 only, raising the resistance thereof to the desired degree without affecting the resistance of the body of the disk at all. Generally, the heating is continued until the resistance of a disk 3 inches in diameter, inch thick, and having a rib or projecting portion about 3 mils high, is so great that it will pass less than one milli-ampere of current at 300 volts.

Generally, the specific resistance of the body portion of the disks is about 50 ohms per centimeter cube, and may be varied between wide limits,

ohms- The height of the ribs may vary say between 25 and 100 within .w'ide limits, beingas low as '1 mil, and I have used disks having ribs as high as 16 mils with success. I

I When .the disks'are stacked, as shown in Fig. 2, with the rib on one side of one disk, in contact with the smooth surface of the adjacent disk a series of spaces 3 are formed between the disks which form starting points for the sparkover and which allow the glow discharge to spread rapidly over the entire surface of the disk. The resistance of the contact points is very high, resulting in an extremely low leakage of current and a neg-.

ligible power loss. The ribs are strong and do not crumble, even though they are sub jected to rough handling.

Although I have described a specific embodiment of my invention, it is apparent that I mayprovide many modifications and variations inprocedure and structure within the scope of this invention. For instance, I may modify the size and shape of the disks, the height'and number of the IlbS or projecting portions and the type of heating plate or ring. Although I utillze amaterial which has a high specific resistance for the entire body of the disk, it is apparent that only the rib portion need have a high specific resistance and that the body portion may be of relatively low resistance materials. The rib, although preferably formed integral with and initially of the same material as the body portion, may be formed separately or of different materials and may be united with the body in any suitable manner. These and other changes may bemade in my invention without departing from the spirit and scope thereof.

I claim as my invention:

1. In a protective device, a substantially plane plate and an elevated portion thereon, this; height thereof being between 1 and 16 m s.

2. In a protective device. a substantially plane plate and an elevated portion thereon,

the height thereof being about 3 mils.

3. In a protective device, a substantially plane late and an elevated portion thereon, said e evated portion having a higher specific resistance than the body of said plate.

4. In' a protective device, a substantially plane plate and a narrow, slightly elevated rtion thereon, said elevated portion having a higher specific resistance than thevbody of said plate.

5. In a protective device, a substantially plane disk and a circular, elevated portion thereon, said elevated portion having a higher specific resistance than the body of said plate.

6. In a protective device, a plurality of plates and conducting spacer members therebetween.

7. In a protective device, a plurality of plates and conduct-ing spacer members having a high specific resistance therebetween.

8. In a protective device, a plurality of lates and conducting spacer members havmg a high specific resistance therebetween and contacting with said plates over a relatively small portion of the area thereof.

9. A method of making plates which comprises forming a plate having an elevated portion thereon and then subjecting said elevated portion to a relatively high tem perature.

10. A method of making plates which comprises forming a plate having an elevated portion thereon, placing said plate so that said elevated portion contacts with a heated member and maintaining said contact until the specific resistance of said elevated portion is raised.

11. A method of making plates which comprises forming a plate having an elevated portion thereon, placing said plate so that said elevated portion contacts with a heated member and maintaining said'contactuntil the specific resistance of said elevated portion is raised until 300 volts applied to a metal plate; in contact with the disc will pass less than 5 milli-amperes.

12. A method of making plates which comprises forming a platehaving an elevated portion thereon and then increasing the resistance of said elevated portion.

13. A plate of high-resistance material comprising a substantially flat body portion and a plurality of rib portions thereon, the resistance of said rib portions being higher than that of the body portion.

14. An excess-voltage discharge device comprising at least one pair of juxtaposed plates, and a high-resistance spacing means on one of the plates interposed between said plates, the resistivity and spacing being such that the discharge device permits a relatively large current-flow at voltages above a predetermined value and prevents-any substalntial current-flow at voltages below said va ue.

15. A protective device comprising at least one pair of juxtaposed high-resistance plates having a discharge gap therebetween. and high-resistance spacing means interposed between said plates and united to one lee ' comprising at least one current-flow at voltages above a 1gap therebetween, at least one of said lates d1 aving an integral rib contacting wit the other plate.

17. An excess-voltage discharge device pair of juxtaposed high-resistance plates having a discharge ap therebetween, at least one of said plates iiaving an integral rib of increased specific resistance contacting with the other plate.

18. A space-current discharge device comprising at least one pair of electrode plates having a discharge gap therebetween, one of said plates carrying a rib contacting with the other plate for spacing the same.

space-current discharge device comprising at least one pair of electrode plates having a discharge gap therebetween, one of said plates carrying a rib contacting with the other plate for spacing the same, the contacting surface of said rib being of higher s ecific resistance than the body portion of tl ie plate which carries it.

20. A space-current discharge device comprising electrode plates having a discharge gap therebetween, the material of at least one of said plates having such resistivity as to cause the discharges in said gap to spread out, said plate carrying a rib contacting with the other plate for spacing the same.

space-current discharge device comprising electrode plates having a discharge gap therebetween, the material of at least one of said plates having such resistivity as to cause the discharges in said gap to spread out, said plate carrying a rib contacting with the other plate for spacing the same, the contacting surface of said rib being of higher specific resistance than the body portion of the plate.

22. An excess-voltage discharge device comprising at least one pair of juxtaposed plates, and a high-resistance spacing means interposed between said plates and united to one of the same, the spacing being such that the space-current flow between the plates always takes the form of a glow discharge.

23. An excess-voltage protective device comprising at least one-pair of juxtaposed b high-resistance plates having a discharge gap therebetween. and a high-resistance spacing means interposed between said plates and united to one of the same, the resistivity and spacing being such that the protective device permits a relatively large redetermined value and prevents any su stantial current-flow at voltages below said value.

protective device comprising stacked electrode plates having: at least one discharge gap therebetween, at' least one of said plates being a substantially plane plate aving a portion elevated mils.

25. A protective stacked electrode plates between 1 and 16 device comprising having at least one scharge gap therebetween, at least one of said plates being a substantially plane plate having an elevated portion of about 3 mils height.

26. A protective device comprising stacked electrode plates having at least one discharge gap therebetween, at least one of said plates being a substantially plane plate of high-resistance material having a. portion elevated between 1 and 16 mils.

7. A protective device comprising stacked electrode plates having at least one ischarge'gap therebetween, at least one of said plates being a substantially plane plate of high-resistance material having an elevated portion of about 3 mils height.

A space-current discharge device comprising at least one pair of electrode plates having a discharge gap therebetween, one of carrying a rib contacting with the other plate for spacing the same, the organization being such as to cause a glow discharge at voltages above a predetermined value and to permit no space-current discharge at voltages materially below said value.

29. A plate of high-resistance material aving portions of the surface thereof of higher resistance than the body portion.

30. A lightning arrester comprlsing a plurality of plates of high resistance material disposed in contact with each other, the contacting portions of one or more of the plates having higher specific resistance than the y portions of the plates.

31. A lightning arrester comprising a plurality of plates of non-metallic material disposed in contact with each other, the contacting ortions of one or more of the plates having igher specific resistance than the body portions of the plates.

32. A l rality of plates of high resistance material disposed in contact with each other at a relatively small number of points, the contacting portions of one or more of the plates having higher specific resistance than the ody portions of the plates.

33. A lightning arrester comprising a plurality of plates of high resistance material,

disposed in contact with each other, the contacting portions of one or more of the plates having higher specific resistance than the body portions of the plates, the spacing and resistivity being such that the space current flow always takes the form of a glow discharge.

35. A lightning arrestercomprismg a plurality of plates of non-metallic material disposed in contact with each other, the contacting portions of one or more of the plates having higher specific resistance than the body portions of the plates, the spacing and resis tivity being such that thespace current flow always takes the form of a glow discharge.

36. A lightning arrester comprising a plurality of plates of high resistance material disposed in contact with each other at a relatively small number of points, the contacting portions of one or more of the'plates having higher specific resistance than the body portions of the plates, the spacing and resistivity being such thatthe space current flow always takes the form of a glow discharge.

37 A lightning arrester comprising a always takes the form of a glow discharge.

2:58. A space-current discharge device comprising electrode plates contacting. at only a relatively small number of points, the remaining portions of the contact surfaces being s aced, the material of at least one of said p ates having such resistivity as to cause the discharges in said gap to spread out in the form of a glow discharge, the

contacting portions of said plate having a higher specific resistance than the spaced portions of the contacting surfaces.

In testimony whereof, I have hereunto subscribed my name this 3rd day of February 1922.

JOSEPH SLEPIAN. 

